On B2G, you can find out your PIDs by using the command ''b2g-ps''
=== How do I disable the sandbox temporarily? ===
export MOZ_DISABLE_CONTENT_SANDBOX=1
and restart Firefox. In B2G's case, this looks like:
adb shell
stop b2g
export MOZ_DISABLE_CONTENT_SANDBOX=1
/system/bin/b2g.sh
== More information ==