How about another spell in the time school.
Time Sphere
4th-level enchantment
Casting Time: 1 action
Range: 150 feet
Components: V, S, M (a tiny ball of tar)
Duration: Concentration, up to 1 minute
You throw a ball of concentrated time at an point in range. All creatures within 30 feet of the point are affected by the spell. You may choose to slow or speed time in the area. If you slow time and a creature starts its turn in a spell or enters the affected area, it must make a Wisdom saving throw. If it fails, the creature instantly loses all its actions, bonus actions, free actions, and ability to move. If you speed time, any creature in the area gains an additional action for the turn. That action can be used only to take the Attack (one weapon attack only), Dash, cast a cantrip, Disengage, Hide, or Use an Object action.
Thoughts?
Throat Punch Games 
do you have to have a check if you are in the area when time is speed up so you do not fall on your face?