What you are talking about we would call this boot into recovery I believe. It's likely throwing people a bit.
Usually on Samsung devices it would be power, volume up and home.
S5 Rogers (Alliance ROM) + Tab S 8.4 wi-fi (Need ROOT!)
Must have Apps: Titanium Backup Pro, AdBlock Plus, Samsung Clock, Kaiten Mail, Business Calendar, Business Tasks, Office Calculator, Next Browser, QuickPic, MXPlayer, Snap Camera, RSSDemon, TrackChecker