Trying to launch phoc from terminal hangs OS

Hi! I'm a total beginner to this and have a feeling I'm just missing something basic, but I haven't been able to find resources anywhere else on what's going on.

I've been trying to launch phoc/phosh on a virtualized Debian instance; they've both compiled/built/installed successfully (according to ninja).

When I try to launch the compositor, this happens:

After the exec line, terminal stops responding to keyboard input (even ctrl+alt+f4), and I have to reboot the VM.

My hunch is that phoc is running, just not on the same display as the terminal--and somehow it's also capturing the keyboard input, making the terminal unusable.

Super nooby issue; sincerest apologies. Really excited about this project! Thanks.