The following packages have had security issues fixed since Sunday:
chromium, gdisk, intel-microcode, connman, golang-1.11, and openjpeg2, privoxy and wireshark
Those are reported for the x86 packages I assume, so for example the intel-microcode revision is very unlikely to bite you. Other things like golang, prixoxy and wireshark are highly unlikely to be installed and even then are generally only install when you need to do something specific. That leaves chromium, gdisk, connman and openjpeg2. You may well have gdisk installed but you're probably not using it so it can't bite you. You either have chromium and connman installed or you don't, and you probably have openjpeg2 installed as a dependency by a web browser, or an office suite, or a graphics package, but I can't say how exploitable this bug is in the wild. Personally, I'd just update rather than spending the time to figure out if I should or not.
Edit: Regarding running emulators simultaneously, if they're windowed, I'd expect them all to run just fine, but maybe a little more slowly. If they're competing for the framebuffer then that behaviour's probably not very well tested and may well result in a crash, but it shouldn't take the machine down. If you lose access to the keyboard you might be forced to reboot, but that's about the worst that should normally happen. And yes, I'd expect doing that would eat thought the battery rather quickly, because I assume they're not using all CPU resources at present. Maybe the screen scaling is taking a chunk of time and CPU ticks though, so perhaps it'll just share those out amongst the three apps and not actually run any harder.
If you want to monitor battery usage, there should be a folder called /sys/class/power_supply/ with a battery folder in it (generally something beginning with 'b') and inside that there should be various files the main on of interest is probably the one called current_now, which'll if you cat it will tell you the current rate of battery drain in something like tenths of a milliamp. You could run something like 'while true; do cat /sys/class/power_supply/b*/current_now; sleep 1; done' to print out the current drain every second or thereabouts.