Cooking a steak that has been left out of the refrigerator for twenty minutes is generally safe. The risk of foodborne illness increases when perishable foods, such as raw meat, are left at room temperature for an extended period. However, a short duration of twenty minutes is unlikely to lead to significant bacterial growth or spoilage.
Bacteria multiply rapidly in the "danger zone," which is the temperature range between 40°F (4°C) and 140°F (60°C). When meat is left out in this temperature range for more than two hours, it becomes unsafe to consume.
In your case, the steak is only left out for twenty minutes, which is well within safe limits. However, it's essential to consider the ambient temperature of the environment. If it's a particularly hot day or the room is warmer than usual, the risk may slightly increase. If you're concerned, you can always use a food thermometer to check the internal temperature of the steak before cooking. The USDA recommends cooking steaks to an internal temperature of 145°F (63°C) for medium-rare and 160°F (71°C) for medium.
As a general rule, to minimize the risk of foodborne illness, it's best to follow proper food safety practices. Refrigerate perishable foods promptly, and if meat or any perishable food has been left out for more than two hours (or one hour if the ambient temperature is above 90°F/32°C), it's best to discard it rather than risking potential illness.