Low risk
Wait a few minutes after the cycle ends, then check for water in the drum. If there is water, drain it through the pump filter before you open the door by hand.
Check the rinse aid first, then the programme, then how the racks are loaded. Only if all three are right and the water is not heating is it a heater or a fault.
Condensation runs down the back wall and out through a small drain hole. When the hole blocks, the water pools at the bottom and may leak onto the floor.
Caution
Check the filter, the moisture sensor, the water tank and the programme. If the dryer smells of burning, stop using it and have it checked.
Describe the job and get a fixed price from a local appliance repair engineer.