[Bug?] iOS call UX improvement, traditional call GUI/chat, transition between them

I don't own an iOS device, this is a friend who's helping me hammer out bugs and such.

When the iOS device receives a riot call (in this case from desktop) you get typical hangup/hold/etc buttons as one would expect in a call.

When minimising riot and doing other call switching stuff, etc, riot can go back to the chat window instead and have the hangup button in the bottom right.

The issue I see here is the jarring transition between the two GUI methods, and I think they should be more seamlessly, and self-evidently, transition(ed/able) between them.

So, for example, have a nice button that you use to switch between the basic call GUI, and the riot chat GUI, back and forth.