PCs entering a room question

[hong]

This thread would have been so much better if it was the PCs entering a bar.

 

[Christian]

2. The PC would be able to adjust his movement if he wants, so he could choose to move to one of the enemies in the E squares instead of going to C. If the E enemies had readied actions to attack, the would have to wait until the PC resolves his movement action before they could use their readied action (since readied actions are immediate reactions, not interrupts)

Actually, immediate reactions can interrupt movement. PHB pg. 268: "The triggering action, event, or condition occurs and is completely resolved before you take your reaction, except that you can interrupt a creature's movement. If a creature triggers your immediate reaction while moving ... you take your action before the creature finishes moving but after it has moved at least 1 square."