Attack powers are primarily intended to be used in combat. That's not their exclusive function - eg the following example of using an attack power to manipulate the fiction in a skill challenge.
Utility powers can be combat-oriented (eg Wrath of the Gods is a damage buff) or non-combat oriented (eg Disguise Self, Ambassador Imp) or useful in either sort of context (eg Arcane Gate, Mighty Sprint).
I don't think that second clause is true at all, either in general or in this case. Who knows what is beyond this room? And the lightning pillars are hardly going to move just to follow the PCs.
In which case you free the NPC before stepping back through the Arcange Gate or the portal (either of which can be open for long enough), or before teleporting out using a warlock power. With a move action economy (as per the example) a single wizard can standard, move (and so get two success) and minor to hold the gate open. A friend can come and help if necessary.
When you're talking about "srategic" teleportation then in 4e you're talking about leveraging the non-combat aspects of the resolution system. Skill and rituals are the premier player-side resources for these (with powers and action points as secondary resources); and the skill check and skill chalenge framework are the primary resolution modes.
My staring point here has always been p 42 of the DMG:
If a character tries an action that might fail, use a check to resolve it. To do that, you need to know what kind of check it is and what the DC is.
Attacks: If the action is essentially an attack, use an attack roll. . . . Use an opposed check for anything that
involves a contest between two creatures.
Other Checks: If the action is related to a skill (Acrobatics and Athletics cover a lot of the stunts characters
try in combat), use that check. If it is not an obvious skill or attack roll, use an ability check.
When it comes to magical phenomena, Arcana comes to the fore, but also Religion for divine magic and presumably Nature for primal magic although that last one has never come up in my actual play. I remember reading accounts online of the use of Arcana to manipulate magical phenomena before I started playing 4e in January 2009. The first example of something along those lines that I remember from play was in what I would guess to be our fourth session, when the player of the paladin had his PC speak a prayer to help fight against an undead creature, which I resolved as a Religion check to grant combat advantage.
There are many published example of using the Arcana skill to modify and manipulate magical effects (see eg skill challenge examples and trap/hazar examples in a range of sources, starting with the 4e DMG). The 4e Rules Compendium, p 136, has these example of improvisation with the Arcana skill:
* Change the visible or audible qualities of one’s magical powers when using them (moderate DC)
* Control a phenomenon by manipulating its magical energy (hard DC)
And for thinking about how rituals fit into this, there's also (on p 78 of the DMG) an example of framing the use of a Speak with Dead ritual as a skill challenge - because the corpse "refuses to be compelled by the power of the ritual", thereby signalling the relationship between fictional situation and mechanical framework.
Here are three actual play examples of this sort of thing, one involving magical phenomena and strategic teleportation as a reult of a skill challenge, one illustrating manipulation of an Arcane Gate via skill check and resource expenditure, and the third illustrating maniuplation of a ritual via Arcana check to get a desired result:
There are no specific rules that cover these sorts of things beyond the general rules for "actions the rules don't cover", skill checks and skill challenges as I've sketched out above. This is why some of us posting in thie thread (eg
@Manbearcat, me) regard 4e as a highly-flexible fiction-first enging, especially outside of combat. It is able to be such a thing partly because it has a very standard resolution system (skill checks, skill challenges) and very straightforward resource suites (powers, hp/healing surges, gp) that allow costs and impacts to be easily assessed and applied.