There's a lot of waiting involved in stepping on the elevator. This makes it an excellent time to chat with your teammates on a run. Unfortunately, stepping on the elevator removes the chat half a dozen times and it keeps messing things up.
Maybe if I type something involving 'r', I'll send half a message to a very confused guy I pm-ed with an hour ago, or maybe I'll speak halfway into the floor and end up with one sentence combined with what I was trying to say on the previous elevator, but gave up on doing.
This is poor user interface. There should only be two things making the chat disappear: Pressing enter to send the message, or double-pressing escape to cancel it. A currently typed message should persist across loading screens, cutscenes, trading windows, anything at all should be completely unable to cancel it, or any other hud interface for that matter.
Usually when i'm talking and then i press like L or M, or other keys that open windows, it will lag me really bad while it is opening it, and pretty much EVERY window will open. Also, while i'm typing it will sometimes make me shoot/swing my sword randomly, and when that happens my teammates probably think i'm eating when they see me standing still and attacking randomly.