diff --git a/Dockerfile b/Dockerfile
index f1318d8..6004f4c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -23,4 +23,6 @@ COPY --from=builder /TestRunner/.build/release/TestRunner bin/
 COPY --from=builder /opt/test-runner/.build .build
 COPY --from=builder /opt/test-runner/Package.resolved Package.resolved
 
+ENV RUN_IN_DOCKER=TRUE
+
 ENTRYPOINT ["./bin/run.sh"]
diff --git a/bin/benchmark-in-docker.sh b/bin/benchmark-in-docker.sh
index a980225..820662e 100755
--- a/bin/benchmark-in-docker.sh
+++ b/bin/benchmark-in-docker.sh
@@ -36,4 +36,4 @@ CURRENT_PATH=${PWD}
 
 hyperfine \
     --parameter-list slug $(find tests -maxdepth 1 -mindepth 1 -type d -printf '%f\n' | paste -sd ",") \
-    "SKIP_DOCKER_BUILD=true bin/run-in-docker.sh {slug} $CURRENT_PATH/tests/{slug} $CURRENT_PATH/tests/{slug}"
+    "bin/run-in-docker.sh {slug} $CURRENT_PATH/tests/{slug} $CURRENT_PATH/tests/{slug}"
diff --git a/bin/run-in-docker.sh b/bin/run-in-docker.sh
index ad63eb0..d37598b 100755
--- a/bin/run-in-docker.sh
+++ b/bin/run-in-docker.sh
@@ -43,5 +43,4 @@ docker run \
     --mount type=bind,src="${INPUT_DIR}",dst=/solution \
     --mount type=bind,src="${OUTPUT_DIR}",dst=/output \
     --mount type=volume,dst=/tmp \
-    -e RUN_IN_DOCKER=TRUE \
     exercism/swift-test-runner $SLUG /solution/ /output/
diff --git a/bin/run-tests-in-docker.sh b/bin/run-tests-in-docker.sh
index aeaa082..6a4e527 100755
--- a/bin/run-tests-in-docker.sh
+++ b/bin/run-tests-in-docker.sh
@@ -28,7 +28,6 @@ for test_dir in tests/*; do
         --mount type=volume,dst=/tmp \
         --workdir "${work_dir}" \
         --entrypoint ${work_dir}/bin/run-test.sh \
-        -e RUN_IN_DOCKER=TRUE \
         exercism/swift-test-runner \
         "${dst_test_dir}"
 
diff --git a/bin/run.sh b/bin/run.sh
index 09178a0..45e53ba 100755
--- a/bin/run.sh
+++ b/bin/run.sh
@@ -25,8 +25,12 @@ SLUG="$1"
 INPUT_DIR="${2%/}"
 OUTPUT_DIR="${3%/}"
 
-WORKING_DIR="${PWD}"
-cp -r "${INPUT_DIR}/." "${WORKING_DIR}"
+if [[ "${RUN_IN_DOCKER}" == "TRUE" ]]; then  
+    WORKING_DIR="${PWD}"
+    cp -r "${INPUT_DIR}/." "${WORKING_DIR}"
+else
+    WORKING_DIR=${INPUT_DIR}
+fi
 
 junit_file="${WORKING_DIR}/results-swift-testing.xml"
 spec_file="${WORKING_DIR}/$(jq -r '.files.test[0]' ${WORKING_DIR}/.meta/config.json)"